over-voltage and pedals

[yanyan]

Preface: i posted this question in another thread almost 2 years ago and got no reply. I'm thinking because it was an old thread and was no longer being followed by other users. The question i posted was and still is of some importance to me and i still haven't found a clear answer. I apologize if re-posting it inconveniences anybody.

For about 2-3 years i used a Roland ACR 9V adapter (that came with my Micro Cube) to power pedals: a Digitech Bad Monkey and a DOD YJM308. Then i learned the ACR adapters are unregulated. I made a reading of the voltage output and it was a whopping 15V. I stopped using the adapter and went back to batteries.

If there was any damage done, would it be noticeable? Perhaps a change in tone? The pedals work fine and sound the same as before - though keep in mind i might very well be in denial. Is it possible to damage the pedal just so that it would keep working yet sound different? Or would damage by over-voltage completely kill 1 or more components rendering the pedal useless?

[bluebunny]

Very few things in a pedal will die with 15V across them (some voltage invertors/boosters can be a bit fragile, e.g. MAX1044).  And not many things in a pedal circuit have the whole power supply voltage across them, anyway (ICs being an obvious exception).  You have damaged nothing.  Rest easy. 

[diffeq]

Welcome, again 

If pedals work, nothing is damaged. Most components can handle up to 25V without breaking a sweat. Like Marc said, MAX1044 is the only component that could burn, but you'd notice that immediately.

...

On a related note, I wish 12V was the standard voltage for pedals. 9V, minus 1.5V dropout on either side of the rail leaves only 6V of headroom.

[ElectricDruid]

Another +1 agree from me. It's unlikely to have killed anything, and if it's working, it's working.

It's probably theoretically possible to damage a pedal and make it sound different, but it's certainly not common and I've never managed it

Tom

[bool]

First you should check the voltage rating of installed components in all your pedals.

In real world, this goes mostly for the electrolytics (aluminum and tantalum), but also for some ICs.

For example, if your pedal has 16V standard electrolytics, you most probably didn't damage anything - but it was a very close margin. Otoh, if your pedal has 16V rated tantalums, with 60% derating (=9,6V), you may have overvolted these caps for a good 5V (this again depends where they are installed - and the "real" in-circuit working voltages).

Things like saying "you're probably ok" over the Internet aren't really reflecting what actually happened. You should check this on per-case basis.

[EBK]

Was the +15V measurement made while it was connected to a pedal, or was it without load?  It is possible you didn't power your pedals with as high of a voltage as you think.

[antonis]

What Eric said..

Most (if not all) of those unregulated supplies exhibit an open circuit voltage much higher than their rated one..
(which voltage falls to nominal even with a light load - e.g. a 9V/1A rated supply may exhibit 13.5v to 15V with no load but set to 9V with a load of 10mA, say..)

[yanyan]

Thank you all very much for the replies.

Was the +15V measurement made while it was connected to a pedal, or was it without load?  It is possible you didn't power your pedals with as high of a voltage as you think.

This measurement was made without any load.

Very few things in a pedal will die with 15V across them (some voltage invertors/boosters can be a bit fragile, e.g. MAX1044).  And not many things in a pedal circuit have the whole power supply voltage across them, anyway (ICs being an obvious exception).  You have damaged nothing.  Rest easy. 

As a form of consolation for myself, as far as the DOD pedal is concerned at least, i have since then replaced the stock 4558 op-amp with a 1458, and replaced the input capacitor as well. So at least those two parts are new.

Another +1 agree from me. It's unlikely to have killed anything, and if it's working, it's working.

It's probably theoretically possible to damage a pedal and make it sound different, but it's certainly not common and I've never managed it

Tom

That's really good to hear, thanks.

What Eric said..

Most (if not all) of those unregulated supplies exhibit an open circuit voltage much higher than their rated one..
(which voltage falls to nominal even with a light load - e.g. a 9V/1A rated supply may exhibit 13.5v to 15V with no load but set to 9V with a load of 10mA, say..)

Thanks. I learned something new today.

Again, thank you all.

[blackieNYC]

Big plus one - the 15v is fine, I'm sure as soon as you plug the pedal in it drops to 9.5 Volts.  The components within have not had to endure 15 V.  They've never seen it. 
Some pedals (digital delays) will want a regulated supply or they will be very noisy or not work. Boss had two 9v supplies -the unregulated ACA, and later, the regulated PSA.  The PSA seems to work on any pedal that originally came with an ACA.